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Question #46536
The Question
A transgenic host cell utilizes RNA interference (RNAi) to defend against a specific viral infection. A researcher attempts to confirm the infection using a direct ELISA targeting the viral capsid protein, which yields a negative result. However, a PCR test on the same tissue confirms the presence of viral DNA. What is the most accurate biological explanation for this observation?
Options
- A.
RNAi mediates post-transcriptional gene silencing of the viral mRNA, resulting in the absence of the antigenic protein required for ELISA detection.
- B.
The viral genome is excised by restriction endonucleases induced by RNAi, leaving only residual DNA fragments detectable by PCR.
- C.
Direct ELISA relies on detecting host antibodies, which are not produced because RNAi neutralizes the virus before an immune response is triggered.
- D.
The RNA-induced silencing complex (RISC) competitively binds to the viral capsid protein, masking the epitopes required for the enzyme-linked antibodies in ELISA.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Regulatory_Failure
Understand how NOT, EXCEPT, and logical constraints are used to manipulate exam results.
Concepts Behind This Question
ELISA|RNAi|Nematode|MALT
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Distinguishing the specific molecular targets of diagnostic tools (PCR for nucleic acids vs.
ELISA for proteins) and integrating them with the exact mechanism of RNAi.
The common misconception is assuming that the presence of a pathogen's genome (PCR positive) guarantees the expression of its antigens.
Students must recognize that RNAi suppresses phenotypic expression at the post-transcriptional level, creating a scenario where DNA is present but the corresponding protein is absent.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Human Health and Disease - Class 12 |
| Concept | ELISA Logic |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |